Introduction: Why Rough-Diamond Sales Changed Forever
In the latest Rapaport Diamond Podcast, Adam Schulman, founder and CEO of Koin International, explained how tenders and auctions reshaped rough-diamond sales. Before tenders became common, miners relied on informal, over-the-table deals. As a result, prices often stayed flat and buyers controlled the market.
During the conversation with Joshua Freedman, Schulman shared how competition improved transparency and why miners now prefer tenders. Because of these changes, auctions and tenders dominate the global trade today.
From Private Bags to Transparent Tenders
For decades, dealers bought rough diamonds in closed rooms, carrying bags of stones and making quick offers. While this approach worked for some, it lacked transparency. Therefore, Schulman saw a gap in the system.
- 2005: He co-founded Fusion Alternatives with I. Hennig. Since it was the first independent tender platform, it allowed small and mid-sized miners to reach more buyers.
- 2015: He launched Koin International to expand the model. After its success, tenders became the preferred sales method.
- Today, over 70% of rough diamonds are sold via tenders or auctions.
At the same time, De Beers and Alrosa continued their sight system. Yet miners shifted toward tenders because they could secure stronger competition and higher prices.
Learn more: How Diamond Auctions Work.
Q&A with Adam Schulman
Q: Why did tenders change the market?
A: Before tenders, miners often had no choice but to accept fixed offers. After tenders gained traction, they attracted hundreds of buyers and achieved 10–15% higher prices.
Q: Why did Koin relocate from Antwerp to Dubai?
A: “During Covid-19, Antwerp became difficult for global access. Meanwhile, Dubai offered lower tax, better logistics, and faster growth,” Schulman explained.
Q: Are tenders the new standard?
A: “Yes. Over time, tenders proved more transparent and competitive, so miners prefer them.”
The Business Impact of Tenders
Because miners wanted fair pricing, tenders delivered results. For example:
- In early Koin tenders, small miners gained 20% more revenue compared to direct deals.
- Dubai now accounts for 40% of global rough-diamond trade, proving its rise as a key hub.
- Koin hosts more than 20 tenders each year, drawing buyers from India, Belgium, Israel, and the UAE.
See also: Why Dubai Became a Diamond Hub.
Adam Schulman Beyond Diamonds
After years of building Koin, Schulman still finds time for his passion: photography. While leading diamond tenders, he also captures wildlife across deserts and safaris. His work appears on Instagram at @adam_s_photography.
For inspiration, explore Gemstone-Inspired Photography.
Adam Schulman, CEO of Koin International, joined the Rapaport Podcast to explain how tenders and auctions changed rough-diamond sales. From Antwerp to Dubai, the shift introduced transparency, competition, and better prices for miners. Today, auctions dominate because they bring more buyers and fairer results.
Suggested Reading:
Guide to Diamond Market Trends
History of Rough-Diamond Trading
Introduction
This comprehensive Watch Buying Guide answers the most common questions about timepieces.
Whether you’re purchasing your first watch or adding to your collection, these expert insights help you make informed decisions.
From understanding movement types to choosing the right size for your wrist, you’ll find everything needed before making a purchase.
What Types of Watches Should You Consider? – Watch Buying Guide Insights
Understanding the five main categories helps narrow your options:
- Mechanical watches – Use springs and gears. No battery needed.
- Quartz watches – Battery-powered; most accurate.
- Automatic watches – Wind themselves from wrist movement.
- Digital watches – Display time numerically on a screen.
- Smartwatches – Connect to your phone and track fitness data.
Accuracy Expectations – Watch Buying Guide Tips
- Quartz watches – Lose about 15 seconds per month.
- Mechanical watches – Lose 20–40 seconds per day.
- Atomic watches – Lose 1 second every 100 million years.
- Your phone’s clock stays perfectly accurate.
Water Resistance Considerations
Water resistance ratings affect usage scenarios:
- 30m – Handles rain and handwashing
- 50m – Safe for swimming
- 100m – Suitable for snorkeling
- 200m+ – Scuba diving
Replace gaskets every 2–3 years to maintain resistance.
Maintenance Schedule – Watch Buying Guide Advice
- Quartz watches – Battery replacement every 1–3 years.
- Mechanical watches – Full service every 3–5 years.
- Service costs: $200–800 depending on the brand.
Watch for stopping, running fast/slow, or condensation under the crystal.
Pricing Strategy
- Budget watches – Plastic cases, basic movements
- Mid-range watches – Steel cases, reliable mechanisms
- Luxury watches – Precious metals, hand-finished details
Remember: craftsmanship, materials, and brand prestige drive prices.
Sizing Advice
- 6–7 inch wrists – 38–42mm
- 7–8 inch wrists – 40–44mm
- 8+ inch wrists – 42–46mm
Ensure lugs don’t overhang wrist edges.
Complications to Prioritize
- Date display – Useful daily
- GMT hand – Second time zone
- Chronograph – Stopwatch
- Moon phase – Decorative
- Annual calendar – Adjusts month lengths
More complications = more things that can break.
Maintenance Tips
- Clean with a soft cloth
- Avoid extreme temperatures & magnets
- Wind manual watches daily
- Use watch winders for automatics
- Don’t adjust date between 9 PM–3 AM
Investment Potential
- Most watches lose value after purchase
- Only select Rolex, Patek Philippe, Audemars Piguet models appreciate
- Vintage watches from 1960s–70s show strong growth
- Buy watches you enjoy wearing, not solely for investment
Essential Tools
- Spring bar tool
- Case back opener
- Soft polishing cloth
- Watch cushion
- Demagnetizer
Where to Purchase
- Online – Better selection, often cheaper
- Physical stores – Try before buying
- Authorized dealers – Full warranties
- Grey market – Discounts, limited warranty
- Forums/eBay – Vintage pieces, verify authenticity
Learn More: